1 Exploiting Parallelism in Geometry Processing with General Purpose Processors and Floating-Point SIMD Instructions

Three dimensional (3D) graphics applications have become very important workloads running on today’s computer systems. A cost-effective graphics solution is to perform geometry processing of 3D graphics on the host CPU and have specialized hardware handle the rendering task. In this paper, we analyze microarchitecture and SIMD in-struction set enhancements to a RISC superscalar processor for exploiting parallelism in geometry processing for 3D computer graphics. Our results show that 3D geometry processing has inherent parallelism. Adding SIMD operations improves performance from 8 % to 28 % on a 4-issue dynamically scheduled processor that can issue at most 2 floating-point operations. In comparison, an 8-issue processor, ignoring cycle time effects, can achieve 20 % to 60 % performance improve-ment over a 4-issue. If processor cycle time scales with the number of ports to the regis-ter file, then doubling only the floating-point issue width of a 4-issue processor with SIMD instructions gives the best performance among the architectural configurations that we examine (the most aggressive configuration is an 8-issue processor with SIMD instructions). Index terms: 3D graphics, geometry pipeline, superscalar processors, SIMD instructions, paired